Optimizer for multiple staged refrigeration systems

ABSTRACT

A method and system for dynamically controlling heaters and compressors of multiple zone heating and cooling systems to modulate supply air temperature values to within a predetermined range and operable in a plurality of stages. The system includes a supply air temperature sensor operable to determine the supply air temperature values. The system also includes a control device configured to determine a plurality of system status conditions and activates and inactivates the heaters and compressors in a plurality of stages based on at least some of the plurality of system status conditions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to U.S. patent application Ser. No.12/653,382,121,409 filed on Dec. 14, 2009 and entitled “Optimizer forSingle Staged Refrigeration Systems”.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

REFERENCE TO SEQUENCE- LISTING, A TABLE, OR A COMPUTER PROGRAM LISTINGCOMPACT DISC APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

1. Technical Field

Embodiments are generally related to packaged multiple zone heating andcooling systems with compression refrigeration systems, and moreparticularly but not limited to use in residential air conditioningsystems, roof top units, water source heat pumps, and air source heatpumps for both residential and commercial buildings.

2. Discussion of Prior Art

Packaged multiple zone heating and cooling systems with compressionrefrigeration systems are widely used in both commercial and industrialsettings. Typical applications include but are not limited to commercialair source heat pump units, commercial water source heat pumps, and rooftop units.

Packaged multiple zone heating and cooling systems with compressionrefrigeration systems typically are comprised of one or more constantspeed compressors, an indoor fan, a return air fan, and a plurality ofterminal boxes. Compressors are staged on and off in stages in order tomaintain the required supply air temperature values.

Speed modulation devices, such as variable speed drives, are ofteninstalled on supply air fans for the purpose of controlling the fanspeed. Controlling the fan speed maintains building or plenum staticpressures as well as at least one terminal box damper in the fully openposition. Variable speed drives are generally installed on return airfans for the purpose of maintaining building or plenum static pressuresand tracking the supply air fan speed. A minimum fan speed is oftenspecified for the supply air fan to prevent system coils from freezing.

A terminal box is often installed for each thermally controlled zone.This terminal box maintains the zone temperature by either modulatingthe reheat (constant terminal box), the airflow (variable air volumeterminal box), or both the airflow and reheat (variable volume withreheat terminal box).

Multiple zone heating and cooling systems that are currently availableare in many ways energy inefficient. When constant speed supply andreturn fans are employed in multiple zone heating and cooling systems,near constant fan power is used regardless of the building load. Asubstantial amount of energy is wasted as a result. Constant air volumeterminal boxes incorporated in the packaged heating and cooling systemsconsume reheat energy at a rate three times greater than-necessary. Whenvariable volume terminal boxes are installed, the constant speed fanover-pressurizes the terminal control box damper. This may potentiallylead to a stuck damper, excessive airflow through the damper, or airflowleakage through the ductwork.

Another problem with multiple zone heating and cooling systems is thatshort cycling of the compressor is a common occurrence. Duringcompressor short cycling, both untreated humid outside air and waterthat has condensed on the coils are carried into the conditioned space.As a result, humidity within the space reaches excessively high levelsand tends to make it susceptible to the accumulation of mold or otherdamage. Short cycling also substantially reduces the life-span of thecompressor and lowers the energy performance of the overall system.

In an effort to lessen the problems associated with short cycling,engineers have installed hot gas by-pass systems in some units ofmultiple stage refrigeration systems. In these systems, a by-pass valveallows compressed gas from the discharge to flow directly back to thesuction side of the compressor when the compressor capacity is higherthan the load. While this method has proven to decrease the occurrenceof short cycling, unreliable system performance has led engineers todisable the control option in practice. A substantial energy penaltyalso results from the use of the hot gas by-pass system.

Engineers have recently introduced but not yet implemented variablecapacity compressor technologies as another way to try to eliminateshort cycling problems. Even with this improved control, however, thesystem is still burdened by cost and energy penalties.

Short cycling is also a major problem associated with multiple stageunits. Due to large incremental capacity changes when one or more stagesare turned on or off, the system capacity does not always match theactual load. The consequent frequent on/off loading or on/off cyclingsubstantially increases system failure rates associated with thecompressors, contactors, and motor windings. This shortens the overalllifespan of the system.

By far the most energy inefficient aspect of packaged multiple stagecooling systems is the current method for keeping system coils fromfreezing. Since there is currently a lack of reliable measuring devices,keeping coils from freezing is only accomplished utilizing a minimum fanspeed. The fan speed is set as high as 70% with a minimum terminal boxairflow of 60%. When both the minimum fan and minimum terminal boxairflow are set on high, the system functions like a constant air volumesystem. As such, the fan power and thermal energy may be two or threetimes higher than needed.

SUMMARY OF THE INVENTION

The following summary of the invention is provided to facilitate anunderstanding of some of the innovative features unique to an embodimentof the present invention and is not intended to be a full description. Afull appreciation of the various aspects of the invention can be gainedby taking the entire specification, claims, drawings, and abstract as awhole.

Accordingly, it is one aspect of an embodiment of the proposed inventionto solve current system problems in packaged multiple zone heating andcooling systems by eliminating compressor short cycling, preventing thecoils from freezing, and minimizing excessive indoor humidity andreheat.

It is another aspect of an embodiment of the proposed invention to lowerthe frequency of short cycling and minimum airflow rates in order toreduce the rate of energy consumption by 20% to 40% and increase thesystem life span by 30% to 70%.

It is a further aspect of an embodiment of the proposed invention tosubstantially lower compressor failure rates and O & M costs by reducingthe rate of on and off cycling.

It is yet a further aspect of an embodiment of the proposed invention toprovide a feasible solution for retrofitting existing systems.

In one embodiment, a method of dynamically controlling heaters andcompressors of multiple zone heating and cooling systems that operate ina plurality of stages and require the use of a supply air temperaturesensor is provided. The method includes providing a controller incommunication with the supply air temperature sensor and operable toreceive supply air temperature values. The method also comprisesobtaining a plurality of system status conditions, and based on at leastsome of the system status conditions stage the heaters and compressorsin a plurality of stages to modulate the supply air temperature valuesto within a predetermined range.

In another embodiment, an optimizer for dynamically controlling heatersand compressors of multiple zone heating and cooling systems to modulatesupply air temperature values to within a predetermined range isprovided. The optimizer includes a supply air temperature sensoroperable to determine the supply air temperature values. A controller islinked in communication with the supply air temperature sensor andconfigured to determine a plurality of system status conditions. Thecontroller activates and inactivates the heaters and compressors in aplurality of stages based on at least some of the system statusconditions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the system embodying the principles ofthe invention used for packaged multiple zone roof top units and ACunits with a compression refrigeration system;

FIG. 2 is a schematic diagram of the system embodying the principles ofthe invention used for packaged multiple zone heat pump systems with acompression refrigeration system; and

FIG. 3 is a flowchart showing the decision-making processes of thecontroller of the system embodying the principles of the invention usedfor packaged multiple zone roof top units, AC units with compressionrefrigeration systems, as well as multiple zone heat pump systems withcompression refrigeration systems.

DRAWINGS REFERENCE NUMERALS

-   100 Supply Air Temperature Sensor-   101 Outside Air Temperature Sensor-   102 Fan of the Rooftop Unit Compressor-   103 Supervisory Controller-   104,105,106,107 Heater Relays of the Rooftop Unit Compressor-   108,109,110,111 Compressor Relays of the Rooftop Unit Compressor-   112 Controller-   114 Rooftop Unit Compressor-   202 Fan of the Packaged Multiple Zone Heat Pump with Compression    Refrigeration System-   204, 205, 206 Heater Relays of the Packaged Multiple Zone Heat Pump    with Compression Refrigeration System-   207 Hot/Cold Switch Valve-   208,209,210,211 Compressor Relays of the Packaged Multiple Zone Heat    Pump with Compression Refrigeration System-   214 Packaged Multiple Zone Heat Pump with Compression Refrigeration    System-   301 Mode Identification Module-   302 Interface Module-   303 Sequence Module-   304 Control Module

DESCRIPTION OF THE PREFFERED EMBODIMENT

The particular values and configurations discussed in these non-limitingexamples can be varied and are cited merely to illustrate an example ofat least one embodiment of the present invention and are not intended tolimit the scope of the invention. Also, it is understood that thephraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” and variations thereof herein is meant toencompass the items listed thereafter and equivalents thereof as well asadditional items. Unless specified or limited otherwise, the terms“mounted,” “connected to,” “linked to”, “attached to,” and variationsthereof are used broadly to encompass both direct and indirectmountings, connections, and supports.

As should also be apparent to one of ordinary skill in the art, thesystems shown in the figures are models of what actual systems might belike. Many of the modules and logical structures described are capableof being implemented in software executed by a microprocessor or asimilar device or of being implemented in hardware using a variety ofcomponents including, for example, application specific integratedcircuits (“ASICs”). Terms like “controller” may include or refer to bothhardware and/or software.

Embodiments of the invention provide an optimizer for multiple zoneheating and cooling systems and methods that can be retrofitted inexisting systems or incorporated into new systems. Embodiments may applybut are not limited to rotary, scroll, screw, and reciprocatingcompressors.

FIG. 1 is a schematic diagram of an embodiment of the invention employedin a packaged multiple zone roof top unit. However, embodiments can alsobe implemented in air conditioning units with compression refrigerationsystems. In one particular embodiment, the optimizer is a plug and playdevice comprised of supply air temperature sensor 100 and controller112. Supply air temperature sensor 100 is linked to controller 112 andfan 102 of existing rooftop unit compressor system 114. Supply airtemperature sensor 100 measures the supply air temperature and sendsthose measurements to controller 112. Supply air temperature sensor 100can be a temperature sensor already incorporated in existing roof topcompressor system 114, an air-conditioning unit with a compressionrefrigeration system (not shown),or incorporated in new systems. Thesupply air temperature sensor can be either digital or analog.

In some embodiments, controller 112 can also be linked to optionalsupervisory controller 103. Supervisory controller 103 sends systeminformation to controller 112 including but not limited to informationon the supply air temperature set point and operating mode. Controller112 is linked in communication with heater relays 104,105,106, and 107,and compressor relays 108, 109, 110, and 111 of existing compressorsystem 114. The relays are turned on and off by controller 112 based onthe system information. The type and design of the relay is not limitedto that illustrated in FIG. 1. When the optimizer is incorporated in newsystems different relays may be designed for use in the new system.

Further, in some embodiments, optional outside air temperature sensor101 can be linked in communication with controller 112. Outside airtemperature sensor 101 is configured to send outside air temperaturevalues to controller 112.

FIG. 2 illustrates an embodiment of the invention incorporated in apackaged multiple zone heat pump with a compression refrigerationsystem. The configuration and operation is identical to the embodimentillustrated in FIG. 1, but with the following differences:

Existing packaged multiple zone heat pump with a compressionrefrigeration system 214 is comprised of heater relays 204, 205, and 206for activating and inactivating heating stages and compressor relays208, 209, 210, and 211 for activating and inactivating cooling stages.As in the embodiment shown in FIG. 1, heater relays and compressorrelays activate and deactivate heater or compressor stages based on thecommands of controller 112. Supply air temperature sensor 100 is linkedto fan 202 of existing packaged multiple zone heat pump with acompression refrigeration system 214. Hot/cold switch valve relay 207from existing system 214 is also linked in communication with controller112. Switch valve relay 207 is configured to receive commands fromcontroller 112 to switch from heating to cooling or cooling to heatingmodes of operation.

FIG. 3 is a flowchart showing the decision-making processes ofcontroller 112 for the embodiments illustrated in FIG. 1 and FIG. 2. Asillustrated in FIG. 3, controller 112 is comprised of modeidentification module 301, interface module 302, sequence module 303,and control module 304.

Interface module 302 functions as an interface between the systemoperator and controller 112 and/or between supervisory controller 103and controller 112. Through such communication, controller 112 obtainsinformation on the system status. Supervisory controller 103 can belinked in communication with controller 112 to send status informationincluding but not limited to data on the minimum and maximum supply airtemperatures for cooling, maximum heating supply air temperature, numberof stages, rotation time period, and the minimum time interval neededbetween system activation and inactivation. As an alternative, thepreviously stated status information may be updated and programmed bysystem operators using human interface methods such as a human operatedcomputer and/or keypad.

Sequence module 303 is configured to periodically change the order ofthe compressors according to a rotation time interval.

When the optimizer is incorporated in a heat pump system, modeidentification module 301 determines the system mode information basedon any one of the methods detailed below.

In a first method, system mode information is received directly fromsupervisory controller 103.

In a second method, the system mode is determined based on outside airtemperature values. Heating mode is assigned when the outside airtemperature is lower than a predetermined value (for example,approximately 40° F.). Cooling mode is assigned when the outside airtemperature is higher than a predetermined value (for example,approximately 65° F.). If the outside air temperature does not satisfyeither of the previously stated conditions, it is assigned to thecirculation/ventilation or free cooling mode.

In a third method, the system mode is determined based on the supply airtemperature values and compressor stages. Circulation/ventilation modeis assigned when the supply air temperature values lie betweenpredefined minimum and maximum cooling set points and the heating andcooling stage is not activated. Heating mode is assigned when one ormore heater stages are activated, or when neither the heater nor thecompressor stages are activated and the supply air temperature valuesare higher than a predefined minimum heating supply air temperaturevalue. Cooling mode is assigned when one or more compressor stages isactivated or neither the heater nor the compressor stage is activatedand the supply air temperature is lower than the maximum cooling supplyair temperature set point.

Control module 304 controls the activity of the compressor and heaterstages based on a set of operating conditions that differ depending onthe application setting. Compressor stages are sequenced on and off tomaintain supply air temperature values in relation to predefined minimumand maximum supply air temperature limits. Staging of the compressorsand heaters ensures adequate building humidity and temperature control.The following gives the specific conditions under which control module304 activates or inactivates the relays for the compressor and heaterstages.

When the heater and compressor stage relays are deactivated and thesupply air temperature is lower than a predetermined minimum temperaturefor heating, or the system is transitioning from the circulation mode tothe cooling mode, a first stage heater relay should be activated.

When the optimizer is applied to roof top or air conditioning units asseen in FIG. 1, first stage heater relay 104 is activated for apredetermined period of time (approximately 5 minutes for example). Ifthe supply air temperature values are lower than a predetermined minimumheating temperature, an additional heater stage such as relay 105 isactivated. If the supply air temperature values are above apredetermined maximum heating temperature, then first stage heater relay104 is deactivated. If the supply air temperature values are above apredetermined maximum cooling temperature, then first stage compressor108 is activated. Likewise, if the supply air temperature values arebelow a predetermined minimum cooling temperature, then first stagecompressor 108 is deactivated. A second compressor stage relay such ascompressor stage relay 109 is activated if supply air temperature valuesare above a predetermined maximum cooling temperature. Additionalcompressor stage relays are activated when the supply air temperaturevalues are above a predetermined maximum cooling temperature anddeactivated when supply air temperature values are below a predeterminedminimum cooling temperature. If the supply air temperature values liebetween minimum and maximum heating temperature values, then controlmodule 304 neither activates nor deactivates heater or compressor stagerelays.

When the optimizer is applied to a heat pump unit as seen in theembodiment shown in FIG. 2, hot/cold switch valve 207 can be set to theheating mode to activate the heater relays. Switching to the heatingmode thereby activates first stage heater relay 204 for a predefinedperiod of time (approximately 5 minutes for example). If the supply airtemperature values are above a predetermined maximum heatingtemperature, first stage heater relay 204 is deactivated. If the supplyair temperature values lie between minimum and maximum heatingtemperature values, then control module 304 neither activates'nordeactivates the compressor stage relays.

If the heater and compressor relays are deactivated and the supply airtemperature is above a predetermined maximum cooling temperature setpoint, or the system is transitioning from cooling mode to circulationmode, switch valve 207 can be set to cooling mode. This will activatefirst stage compressor relay 208.

If supply air temperature values drop below a predetermined minimumcooling temperature (for example approximately 45° F.), first stagecompressor relay 208 is deactivated. If supply air temperature valuesrise to a temperature over the predetermined maximum cooling temperature(for example approximately 65° F.) in a predetermined time period (forexample, approximately two minutes), an additional compressor stagerelay is activated.

The following gives the specific conditions for different settings underwhich control module 304 activates or inactivates compressor stages (iftwo or more compressor stages are already active).

When the optimizer is applied to roof top units or heat pumps in thecooling mode, an additional compressor stage relay is activated ifsupply air temperature values are above a predetermined maximumtemperature. If supply air temperature values are below a predeterminedminimum temperature, one compressor stage relay is deactivated.

When the optimizer is applied to heat pumps in the heating mode, anadditional compressor stage relay is deactivated if the supply airtemperature is above a predetermined maximum temperature. If supply airtemperature values are lower than a predetermined minimum temperaturevalue, additional compressor stage relays are activated.

The optimizer proposed in this application identifies both thecompressor and fan faults using patented technologies developed in thepast. The programming of controller 112 is not detailed in thisdisclosure but is known to a person of ordinary skill in the art.

Various features and advantages of the invention are set forth in thefollowing claims.

What is claimed is:
 1. A method of dynamically controlling heaters andcompressors of a multiple zone heating and cooling system operable in aplurality of heater stages and compressor stages including a supply airtemperature sensor, the method comprising: providing a controller incommunication with said supply air temperature sensor and operable toreceive supply air temperature values from said supply air temperaturesensor; obtaining a plurality of system status conditions; staging saidplurality of heater stages and compressor stages to modulate said supplyair temperature values to within a predetermined range based on at leastsome of said system status conditions.
 2. The method of claim 1, whereinsaid multiple zone heating and cooling system is a packaged multiplezone heat pump with compression refrigeration system.
 3. The method ofclaim 1, wherein said multiple zone heating and cooling system is arooftop unit compressor.
 4. The method of claim 1, wherein saidplurality of system status conditions comprise at least one of a minimumsupply air temperature for cooling, maximum supply air temperature forcooling, maximum supply air temperature for heating, rotation timeperiod, number of compressor stages, and minimum time interval betweensystem activation and inactivation.
 5. The method of claim 1, whereinobtaining a plurality of system status conditions further comprisesproviding at least one additional controller in communication with andoperable to send said plurality of system status conditions to saidcontroller.
 6. The method of claim 1, wherein staging said plurality ofheater stages and compressor stages to modulate said supply airtemperature values to within a predetermined range based on at leastsome of said system status conditions further comprises determining asystem operating mode.
 7. The method of claim 6, wherein determining asystem operating mode further comprises providing at least oneadditional controller in communication with and operable to send saidsystem operating mode to said controller.
 8. The method of claim 6,wherein determining a system operating mode further comprisesdetermining said system mode in at least one of a heating mode, acooling mode, and a ventilation/circulation mode.
 9. The method of claim8, wherein determining a system in at least one of a heating mode, acooling mode, and a ventilation/circulation mode further comprises:providing an outside air temperature sensor in communication with saidcontroller; measuring outside air temperature values with said outsideair temperature sensor; comparing said outside air temperature valueswith a predetermined outside air temperature value; assigning saidheating mode when said outside temperature values are lower than saidpredetermined outside air temperature value; assigning said cooling modewhen said outside air temperature values are higher than saidpredetermined outside air temperature value; assigning saidcirculation/ventilation mode when said outside air temperature valuesare neither higher than said predetermined outside air temperature valuenor lower than said predetermined outside air temperature value.
 10. Themethod of claim 8, wherein determining a system operating mode in atleast one of a heating mode, a cooling mode, and acirculation/ventilation mode further comprises: assigning said coolingmode when said supply air temperature values are lower than a maximumcooling supply air temperature set point and at least one of saidplurality of compressor stages is active; assigning said cooling modewhen said supply air temperature values are lower than a maximum coolingsupply air temperature set point and all of said plurality of compressorstages and heater stages are inactive; assigning said heating mode whensaid supply air temperature values are above a predetermined minimumheating supply air temperature value and at least one of said pluralityof heater stages is active; assigning said heating mode when said supplyair temperature values are above a predetermined minimum heating supplyair temperature value and all of said plurality of compressor stages andheater stages are inactive; assigning said circulation/ventilation modewhen said supply air temperature values are between a predeterminedminimum and maximum cooling set point and said plurality of compressorstages and heater stages are inactive.
 11. The method of claim 3,wherein staging said plurality of heater stages and compressor stages tomodulate said supply air temperature values further comprises:activating a first heater stage for a predetermined period of time;activating an additional heater stage when said supply air temperaturevalues are lower than a predetermined minimum heating temperature;deactivating said first heater stage when said supply air temperaturevalues are above a predetermined maximum heating temperature; activatinga first compressor stage when said supply air temperature values areabove a predetermined maximum cooling temperature; deactivating saidfirst compressor stage when said supply air temperature values are belowa predetermined minimum cooling temperature; activating a secondcompressor stage when said supply air temperature values are above apredetermined maximum cooling temperature; deactivating said secondcompressor stage when said supply air temperature values are below apredetermined minimum cooling temperature; activating additionalcompressor stages when said supply air temperature values are above apredetermined maximum cooling temperature; deactivating said additionalcompressor stages when said supply air temperature values are below apredetermined minimum cooling temperature.
 12. The method of claim 2,wherein staging said plurality of heater stages and compressor stagesfurther comprises the steps of: activating a first heater stage for apredetermined period of time and setting said hot/cold switch valve tosaid heating mode; deactivating said first heater stage when said supplyair temperature values are above a predetermined maximum heatingtemperature; activating a first compressor stage when said heater stagesand compressors stages are deactivated, said supply air temperaturevalues are above a maximum cooling temperature set point, and saidhot/cold switch valve is set to said cooling mode; activating a firstcompressor stage when transitioning from said cooling mode to saidcirculation mode, and said hot/cold switch valve is set to said coolingmode; deactivating said first compressor stage when said supply airtemperature values are below a predetermined minimum cooling temperaturevalue; activating a second compressor stage when said supply airtemperature values are above a predetermined maximum cooling temperaturevalue in a predetermined period of time; deactivating said secondcompressor stage when said supply air temperature values are below apredetermined minimum cooling temperature value; activating additionalcompressor stages when said supply air temperature values are above apredetermined maximum temperature value in said cooling mode and when atleast two or more compressor stages are already active; deactivatingsaid additional compressor stages when said supply air temperaturevalues are below a predetermined minimum temperature value in saidcooling mode and when at least two or more compressor stages areactivated; activating an additional compressor stage when said supplyair temperature values are below a predetermined minimum temperaturevalue in said heating mode and when at least two or more compressorstages are activated; deactivating an additional compressor stage whensaid supply air temperature values are above a predetermined maximumtemperature value in said heating mode and when at least two or morecompressor stages are activated.
 13. An optimizer for dynamicallycontrolling heaters and compressors of a multiple zone heating andcooling system to modulate supply air temperature values to within apredetermined range, the optimizer comprising: a supply air temperaturesensor operable to determine said supply air temperature values; acontrol device linked in communication with said supply air temperaturesensor and configured to determine a plurality of system statusconditions, and based on at least some of said plurality of systemstatus conditions, activate and inactivate said heaters and compressorsin a plurality of stages.
 14. The optimizer of claim 13, wherein saidplurality of system status conditions are further comprised of at leastone of a minimum and maximum supply air temperature for cooling, amaximum heating supply air temperature, number of stages, rotation timeperiod, and minimum time interval between system activation andinactivation.
 15. The optimizer of claim 13, further comprising: anoutside air temperature sensor linked in communication with said controldevice and operable to measure outside air temperature values; asupervisory controller linked in communication with said control deviceand operable to send said plurality of system status conditions to saidcontrol device.
 16. The optimizer of claim 13, wherein said controldevice is further comprised of a plurality of modules comprising: aninterface module configured to interface said system information betweena human operator and said control device and from an additionalcontroller and said control device; a sequence module configured toalter the order of said heaters and compressors based on a rotation timeinterval; a mode identification module configured to determine aplurality of operating modes; a control module configured to activateand inactivate said heaters and compressors in said plurality of heaterstages and compressor stages.
 17. The optimizer of claim 16, whereinsaid mode identification module is further configured to determine saidplurality of operating modes in one of: a cooling mode when said supplyair temperature values are lower than a maximum cooling supply airtemperature set point and at least one of said plurality of compressorstages is active; a cooling mode when said supply air temperature valuesare lower than a maximum cooling supply air temperature set point andall of said plurality of compressor stages and heater stages areinactive; a cooling mode when outside air temperature values are higherthan a predetermined outside air temperature value; a heating mode whensaid supply air temperature values are below a predetermined minimumheating supply air temperature value and at least one of said pluralityof heater stages is active; a heating mode when said supply airtemperature values are above a predetermined minimum heating supply airtemperature value and all of said plurality of compressor stages andheater stages are inactive; a heating mode when outside air temperaturevalues are lower than a predetermined outside air temperature; acirculation/ventilation mode when said supply air temperature values arebetween a predetermined minimum and maximum cooling set point and saidplurality of compressor stages and heater stages are inactive; acirculation/ventilation mode when outside air temperature values areneither higher than a predetermined outside air temperature value norlower than said predetermined outside air temperature value.
 18. Theoptimizer of claim 13, wherein said multiple zone heating and coolingsystem is a rooftop unit compressor operable in a plurality of heaterstages and compressor stages further comprising: a first heater stageoperable to activate for a predetermined period of time, and operable todeactivate when said supply air temperature values are above apredetermined maximum heating temperature; additional heater stagesoperable to activate after the activation of said first heater stagewhen said supply air temperature values are higher than a predeterminedminimum temperature, and operable to deactivate when said supply airtemperature values are below a predetermined minimum temperature; afirst compressor stage operable to activate when said supply airtemperature values are higher than a predetermined maximum temperature,and operable to deactivate when said supply air temperature values arelower than a predetermined minimum temperature; additional compressorstages operable to activate after the activation of said firstcompressor stage when said supply air temperature values are above apredetermined maximum temperature, and operable to deactivate when saidsupply air temperature values are below a predetermined minimumtemperature.
 19. The optimizer of claim 13, wherein said multiple zoneheating and cooling systems is a packaged multiple zone heat pump withcompression refrigeration system comprising: a plurality of relaysconfigured to operate said heaters and compressors in a plurality ofheater stages and compressor stages; a switch valve operable totransition said packaged multiple zone heat pump with compressionrefrigeration system between one of a cooling mode and a heating mode.20. The optimizer of claim 19, wherein said plurality of heater stagesand compressor stages further comprise: a first heater stage operable toactivate for a predetermined period of time when said hot/cold switchvalve is in said heating mode, and operable to deactivate when saidsupply air temperature values are above a predetermined maximum heatingtemperature; a first compressor stage operable to activate when saidsupply air temperature values are above a predetermined maximum coolingtemperature set point and said hot/cold switch valve is set in saidcooling mode, and operable to deactivate when said supply airtemperature values are below a predetermined minimum cooling temperaturevalue; a second compressor stage operable to activate when said supplyair temperature values are above a predetermined maximum coolingtemperature value in a predetermined time period, and operable todeactivate when said supply air temperature values are below apredetermined maximum cooling temperature value; additional compressorstages operable to activate when said supply air temperature values areabove a predetermined maximum temperature value in said cooling mode,and operable to deactivate when said supply air temperatures are below apredetermined minimum temperature value in said cooling mode; additionalcompressor stages operable to activate when said supply air temperaturevalues are below a predetermined minimum temperature value in saidheating mode, and operable to deactivate when said supply airtemperature values are above a predetermined maximum temperature valuein said heating mode.